Where was Tenochtitlán?
Tenochtitlán was built on an island in Lake Texcoco in the Valley of Mexico, on the site of modern-day Mexico City. Connected to the mainland by causeways, the Aztec capital housed 200,000–300,000 people and was one of the largest cities in the world when the Spanish arrived in 1519.
Tenochtitlán, the capital of the Aztec Empire, was located on an island in Lake Texcoco in the Valley of Mexico — the broad, high-altitude basin that today holds Mexico City. The city was founded in 1325 CE, according to Aztec tradition, on the spot where an eagle was seen perching on a cactus and eating a snake — an image that appears on the modern Mexican flag.
The location was initially unpromising — a small, marshy island that more powerful groups had ignored. But the Aztecs (Mexica) transformed this disadvantage into an asset. The lake provided natural defense against attack, fresh water for agriculture (though Lake Texcoco itself was brackish), and a transportation network of canals. Through the construction of chinampas — artificial agricultural islands — the Aztecs dramatically expanded the island's area and agricultural productivity.
By the early 16th century, Tenochtitlán had become one of the world's largest cities, with a population estimated at 200,000 to 300,000. Three major causeways connected the island to the mainland, and aqueducts brought fresh water from springs at Chapultepec. The city was centered on a massive ceremonial precinct dominated by the Templo Mayor pyramid-temple, surrounded by palaces, markets, schools, and residential neighborhoods.
After the Spanish conquest of 1519–1521, Hernán Cortés ordered the destruction of Tenochtitlán and the construction of Mexico City on its ruins. Lake Texcoco was gradually drained over the following centuries. Today, the remains of the Templo Mayor can be visited in the heart of Mexico City's historic center, a few steps from the main cathedral — which was itself built with stones from demolished Aztec temples.